Low weight gain in baby girl of 3 month.

My baby girl is 88 days old. Her weight during birth was 2.5 kg first month wt gain was ok 3.1 kg ( during hospital discharge weight was 2.4 kg) full term delivery. Last month she gain very less wt around 350 gm and reached till 3.5 kg. Current wt is 3.73kg. pediatrician suggested to take powder twice lactodex, simyl mct oil After a week weight gain was 70gms . So he asked for few blood test heamoglobin - 9.5,sgpt(alt) 72.6,absolute lymphocyte count-3478.asked for colour doppler,chest xray which is also normal ( as baby make wheezing sound).He mentioned the reason could be laryngomalacia.So the doctor concludes that poor weight gain pattern could be because of breathing exhaustion. It will rectify on its own once laryngomalacia subsides with age.she smiles, play with her hand, eat her fist , pee 8-10 time normal in colour , poops 4-5 times yellow in colour.everything seems normal in her activity.completely breast fed 7-8 times. what is the reason for low wt gain.is this normal and ok?